Circuit interrupter with improved contact structure and arc-runner

ABSTRACT

A circuit breaker comprises an improved arcing-contact and arcrunner contact structure with a resiliently mounted construction.

United States Patent Inventors Appl. No.

Filed Patented Assignee Eugene J. Walker;

James P. Ellsworth, Beaver; Alfred E. Meier, Beaver Falls, allot, Pa. 700,251

Jan. 24, 1968 June 15, 1971 Westinghouse Electric Corporation Pittsburgh, Pa.

CIRCUIT INTERRUPT ER WITH IMPROVED CONTACT STRUCTURE AND ARC-RUNNER 17 Claims, 13 Drawing Figs.

US. Cl

Field of Search 200/147 Int. Cl ..H01h 33/12 l/IIII/Il/I Primary Examiner- Robert S. Macon Attorneys-A. T. Stratton, C. L. McHale and W. A. Elchik ABSTRACT: A circuit breaker comprises an improved arcingcontact and arc-runner contact structure with a resiliently mounted construction.

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' k\\\\\\\\\\\ I47 I43 F IG.I3. INVENTORS Eugene J. WalkenJomes P Ellsworth and Alfred E. Moier.

BY WM 5 5 W ATTORNEY CIRCUIT INTERRUPTER WITI-I IMPROVED CONTACT STRUCTURE AND ARC-RUNNER Cross-Reference to Related Application Certain features of the circuit breaker herein disclosed are disclosed in the copending patent application of Alfred E. Maier et al., Ser. No. 700,248, filed concurrently herewith and in the copending patent application of Albert R. Cellerini et al., Ser. No. 765,1.43, filed Oct. 25, 1968 which was a continuation of a parent application Ser. No. $42,536 that was filed on Apr. l4, I966.

Background of the Invention It is desirable that the current carrying contacts of a circuit breaker be kept clean and undamaged so that the breaker will carry normal current without undue heating. Thus, an object of this invention is to provide an improved circuit breaker with a resiliently mounted arcing-contact and arc-runner constructed to draw and carry arcs in order to protect other contacts in the breaker.

Summary of the Invention An improved circuit breaker is provided with a contact structure comprising a resiliently mounted arcing-contact and arc-runner constructed to draw arcs and carry the arcs into an arc-extenguishing structure where the arcs are extinguished.

Brief Description of the Drawings FIG. I is a side sectional view, with parts broken away, and with parts indicated by broken lines, of a circuit breaker embodying the principal features of this invention;

FIG. 2 is a side sectional view of one of the movable contact structures of the circuit breaker seen in FIG. 1;

FIG. 3 is a sectional view, with parts broken away, illustrating the contact means and part of the operating mechanism from the center pole of the three-pole circuit breaker of FIG. 1;

FIGS. 4, 5 and 6 are side views, with parts broken away, illustrating three different positions of one of the movable contact structures during an opening operation of the circuit breaker;

FIG. 7 is a partial view, enlarged relative to FIGS. 1-6, illustrating the direction of current flow during an interrupting operation;

FIG. 8 is a top plan view, with parts broken away, of the stationary contact structure of FIG. 7;

FIGS. 9l2 are partial side views, with parts broken away and with parts shown in section, of a modified form of the invention; and

FIG. 13 is a top plan view looking in the direction of the XIII-XIII arrows of FIG. 12.

Description of the Preferred Embodiments Referring to the drawings, there is shown, in FIG. 1, a molded case or insulating-housing circuit breaker 5. The circuit breaker is of the type more specifically described in the above-mentioned copending patent application of A. E. Maier et al., Ser. No. 700,248. Thus, only a brief description of the circuit breaker is given herein. The circuit breaker 5 comprises an insulating housing 7 having barrier means 8 separating the housing into three adjacent compartments for housing the three pole units of the multipole circuit breaker in a manner well known in the art. In each pole unit, a pair of solderless terminals 15, 17 are provided at the'opposite ends of the compartment to enable connection of the circuit breaker in an electric circuit.

In each of the three pole-unit compartments there is a rigid stationary conductor 9 and a rigid stationary conductor 11, both of which conductors are fixedly secured to the housing 7. A stationary contact 13 is fixedly secured to the conductor 9, and a stationary contact 15 is rigidly secured to the conductor 1 1. Another stationary or fixed contact 17 is fixedly secured to the conductor 11, and an arcing contact structure indicated generally 'at 19 is secured to the conductor 11 for drawing and carrying arcs in a manner to be hereinafter more specifically described. A conductor 21, that is secured at one end thereof to the conductor 9 and at the other end thereof to the terminal 17, passes through an opening in a removable trip device indicated at 25. The removable trip device 25 is a thermal-magnetic trip device comprising a latch 27 that is automatically operated in response to overload current through any of the pole units of the circuit breaker to effect tripping operations of the circuit breaker in a manner well known in the art. The trip device 24 is of the type described in the patent to A. R. Cellerini et al., U.S. Pat. No. 3,141,081.

A single operating mechanism 29, which comprises an insulating handle 31 that extends through an opening 33 in the front of the housing 7, is connected to a movable contact structure 35 in the center pole unit by means of a pivot pin 37. The operating mechanism 29 comprises a U-shaped operating lever 39 pivotally supported on pins 41 that are supported on a frame 42. The operating mechanism 29 also comprises a pair of toggles 43, 45 and overcenter spring means 47. The spring means 47 is connected at one end to the operating lever 39 and at the other end to a knee pivot 49 that connects the toggles 43, 45. The upper toggle link 45 is pivotally connected to a trip member 51 that is pivotally supported at 53 and to the knee pivot 49 of the toggle 43, 45. The lower toggle link 43 is pivotally connected to a contact support member 57 by means of the pin 37.

The contact support member 57 is an inverted generally U- shaped rigid metallic support member that is supported for pivotal movement about a pin 59 that is supported on the supporting frame 42 in the associated pole-unit compartment. The contact support member 57 is fixedly connected to an insulating tie bar 63 by means of a metallic supporting bracket 65. The three contact support members 57 for the'three pole units are all similarly connected to the common tie bar 63 for simultaneous operation in a manner to be hereinafter described.

The contact support member 57 is part of the movable contact structure 35 that is more specifically described in the above-mentioned copending application of Alfred E. Maier, Ser. No. 700,248. The movable contact structure 35 comprises a conducting arcing-contact arm 69 and four conducting bridging main contact arms 71. The arcing-contact arm 69 is supported intermediate the bridging main contact arms 71 with two of the four bridging main contact arms 71 being supported on one side of the arcing-contact arm 69 and with the other two of the bridging contact arms 71 supported on the opposite side of the arcing-contact arm 69. The pin 59, which is supported on the associated supporting frame 42, extends through openings in the opposite legs of the U-shaped contact support member 57 to pivotally support the support member 57.- As can be seen in FIG. 2, the pin 59 also extends through openings 73 in the bridging contact arms 71. Another pin 75 extends through elongated slots 77 (FIG. 4) in the four main contact arms 71 to also provide support for the main contact arms 71. The openings 73 are larger in diameter than the pin 59 and the openings 77 are elongated in the direction shown for a purpose to be hereinafter described. The pin 75 also extends through an opening 81 (FIG. 2) in the arcing-contact arm 69 with the pin fitting snugly in the opening 81 so that the arcing-contact arm 69 is supported for pivotal movement about the axis of the pin 75. A coil spring 83 biases the arcingcontact arm 69 in a counterclockwise direction about the pin 75. Counterclockwise movement of the arcing-contact arm 69 is limited by engagement of an end portion 85 thereof with the bight portion of a U-shaped separating member 87. The U- shaped separating member 87 is a rigid metallic member that is welded or otherwise fixedly secured to the bight portion of the contact support member 57, with the opposite legs of the U-shaped member being positioned on opposite sides of the arcing-contact arm 69 spaced from the arcing-contact arm 69 in order to prevent the application of side force or side thrust from the main contact arms 71 against the arcing-contact arm 69 so that the arcing-contact arm 69 will be free to pivot on the pin 75. The force or side thrust is a result of the magnetic forces that are generated by the current which passes through the arcing-contact arm 69 and main contact arms 71 in parallel paths and that tend to squeeze the contact arms together. A separate pair of coil springs 91 and 93 is positioned between each main contact arm 71 and the bight portion of the U- shaped separating member 87 to bias the main contact arm 71 to provide contact pressure in the closed position of the contacts. Each of the main contact arms 71 is provided with a contact 95 at one end thereof for cooperating with the as sociated stationary contact and a contact 97 in proximity to the other end thereof for cooperating with the associated stationary contact 13. The arcing-contact arm 69 is provided with a contact 99 for cooperating with the stationary or fixed contact 17 (FIG. 1) and for cooperating with an arcing contact 101 that is supported on the free end of a resilient conductor 103. The arcing-contact arm 69 is electrically connected to the rigid fixed conductor 9 by means of a flexible conductor 105.

As will be best understood with reference to FIGS. 7 and 8, the resilient conductor 103 is a leaf-spring conducting member comprising a lower part 111 that is secured to the conductor 11 by means of a pair of rivets 112 and an upper part 1 15 at the free end thereof for supporting the arcing contact 101. An elongated flat magnetic steel plate arc-runner 119 is secured at the upper end thereof to the resilient conductor 19 by means of a pair of rivets 121. The elongated arcrunner 119 is secured, at only the upper end thereof, to the resilient conductor 19, and the main body part of the elongated arc-runner is spaced from the resilient conductor 19.

In each pole unit, there is an arc-extinguishing structure 125 comprising an insulating casing 127 and a plurality of stacked spaced magnetic plates 129 secured in the casing 127. The plates 129, in top plan view, are generally U-shaped structures supported with the openings aligned and positioned such that the movable arcing-contact arm 96 moves within the aligned openings during opening and closing operations of the contacts. During opening of the contacts, the magnetic field around the arc, operating on the magnetic plates 129, draws the arc inward (to the left as seen in FIG. 1) toward the bight portions of the U-shaped magnetic plates where the arc is broken into a plurality of serially related arc portions to be extinguished in a manner well known in the art.

The circuit breaker is shown in FIG. 1 in the open or off" position with the trip member 51 in the latched position. In order to close the circuit breaker, the handle 31 is moved in a counterclockwise direction about the pivot 41 to operate the springs 47 to erect the toggle 43, 45 to thereby rotate the contact support member 57 of the center pole unit in a counterclockwise direction about the pivot 59 to the closed position seen in FIG. 3. With the three contact support members 57 being supported on the tie bar 63 for simultaneous movement,

this movement operates to simultaneously move all three of the contact support members 57 to the closed position. When it is desired to manually open the circuit breaker, the handle 31 is moved in a clockwise direction about the pivot 41 to operate the springs 47 to cause collapse of the toggle 43, 45 to thereby move the contact support member 57 of the center pole unit to the open position seen in FIG. 1. This movement, because all the contact support members are supported for simultaneous movement on the tie bar 63, moves all three of the contact support members 57 to the open position. Each of the movable contact support members 57 moves about the associated pin 59 with all of the movable contact members moving about a common axis.

When the circuit breaker is in the closed position and an overload current above a predetermined value occurs in any of the three pole units, the trip device 25 is operated to automatically release the latch structure 27 to thereby release the trip member 51. Upon release of the trip member 51, the

springs 47 act to rotate the trip member 51 in a counterclockwise direction about the pivot 53 to cause collapse of the toggle 43, 45 and movement of the three contact support members 57 to the open position in a manner will known in the art. Upon tripping movement of the circuit breaker the handle 31 is moved to an intermediate position to provide a visual indication that the circuit breaker has been tripped. The circuit breaker is trip free in that the breaker will trip even if the handle is manually held in the closed position.

It is necessary to reset and relatch the circuit breaker mechanism, following an automatic opening or tripping operation, before the contacts can be closed. Resetting and relatching is effected by moving the handle 31 to the extreme off" or open position. During this movement, a shoulder 131 on the operating lever 39 engages a shoulder 133 on the trip member 51 to move the trip member 51 in a clockwise direction. At the end of this movement, the free or latching end of the trip member 51 is reengaged and relatched with the latch structure 27 in a well known manner. The circuit breaker can than be manually operated in the same manner as was hereinbefore described.

The contacts are shown in FIG. 3 in the closed position. In this position, the spring 83 biases the arcing-contact arm 69 in a counterclockwise direction about the pin 75 to provide contact pressure between the arcing movable contact 99 and the fixed or stationary contact 117. The resilient conductor 103 is constructed and arranged such that in the open position of the contact the arcing contact 101 is in a position higher, a limited distance, than the position shown in FIG. 3. Thus, with the arcing-contact arm 69 in the closed position seen in FIG. 3 the resilient conductor 103 is biased downward to a charged condition. Each pair of springs 91, 93 biases the associated main contact arm 71 downward to provide contact pressure between the contacts 95, 15 and between the contacts 99, 13.

In the closed position of the contacts, the circuit through each pole extends from the terminal 17 through the conductor 21, the conductor 9, the stationary contact 13, the four movable contacts 97, the four main contact arms 71, the four moveable contacts 95, the stationary contacts 15, the conductor 11 to the other terminal 15. The four main contact arms 71 carry most of the current in the closed position of the contacts. A parallel current path bridges the conductors 9 and 11 through the flexible conductor 105, the arcing-contact arm 69, and the contacts 99, 17. In addition to the current that passes from the arcing-contact arm 69 through the contacts 99, 17 to the conductor 11, a parallel conducting path extends from the arc contact 99 through the contact 101 and resilient conductor 103 to the conductor 11. Because the contacts 95, 15 and 97, 13 are relatively low resistance contacts relative to the contacts 99, 17, 101, most of the current bridging the conductors 9 and 11 in the closed position of the contacts will flow through the four main contact arms 71.

During the opening operation of the circuit breaker, the contact support member 57 moves in a clockwise direction about the pivot 59. During the opening operation, the contacts first move from the position shown in FIG. 3 to the position shown in FIG. 4 in which position the contacts 95, 15 have separated before the contacts 99, 13 separate and before the contact 99 separates from the contacts 17, 101. During this initial movement, the pin 75 moves in the slots 77 from the lower end of the slots to the upper end of the slots with the springs 91, 93 biasing the main contact arms 71 downward until the pin 75 engages the upper ends of the slots whereupon the contact arms 71 move with the contact support member 57. When the contacts 95, 15 separate, the current is all carried by the contact arm 69 and flexible conductor 103 since the current flow through the main contact arms 71 is interrupted. During this movement from the FIG. 3 to the FIG. 4 position, the spring 83 biases the arcing-contact arm 69 in a counterclockwise direction about the pin 75 so that the arcing movable contact 99 remains in engagement with the contacts 17, 101. As the opening movement continues, the part 85 of the arcing-contact arm 69 engages the member 87 to limit counterclockwise movement of the arcing-contact arm 69 about the pin 75 whereupon the arcing-contact arm 69 will then move as a unit with the contact support member 57. As the parts move to the position seen in FIG. 5, the contact 101, under the bias of the charged leaf spring conducting support member 103, follows the contact 99 a limited distance to provide that the contacts 99, 17 separate before the contacts 99, 101 separate so that in the position shown in FIG. 5, the full current is carried through the contacts 99,101. As the contacts move from the position shown in FIG. 5 to the position shown in FIG. 6, the arcing contact 99 separates from the arcing-contact 101 drawing an are 139 that moves upward on the arcing-contact arm 69 and outward (to the left) along the arcrunner 119 into the arc plates 129 where the arc is broken up by the arc plates 129 into a plurality of serially related arcs to be extinguished. As was previously set forth, and as can be seen in FIG. 7, the elongated arc-runner l19 is secured at only the upper end thereof to the conductor 103, and the lower end of the arc-runner 119 is free with the main body part of the arc-runner being spaced from the conductor 103. With this construction, the current through the arcing-contact arm 69, the arc, the arc-runner 119 and flexible conductor 103 forms an inside loop at A" and an inside loop at B, with the are moving in the direction of the arrow (FIG. 7) toward the bight portions of the arc plates (FIG. 1), so that the loop effect contributes in moving the are into the arc plates. For certain applications, it may be desirable to place an insulator between the main body part of the arc-runner 119 and the flexible conductor 103 to prevent the drawing of an are between these members during circuit interruption.

During the closing operations, the reverse sequence of contact engagement takes place as the contacts move from the FIG. 1 to the FIG. 3 position. During this movement, the contact 97 will first engage the contact 13(FIG. 6). Then the contact 99 will engage the contact 101 as shown in FIG. 5. Thereafter, the contact 99 will engage the contact 17, and finally the contact 95 will engage the contact 15. During this movement, the arcing-contact arm 69 moves initially as a unit with the contact support member 57 until the contact 99 engages the fixed contact 17. Thereafter, the arcing-contact arm 69 will pivot clockwise about the pin 75 as the contact support member 57 moves to the fully closed position. When the contacts 95, first engage, the pin 75 is at the upper portion of the slots 77. After the initial engagement between the contacts 95, 15, as the contact support member 73 moves to the fully closed position, the springs 91, 93 are charged and the pin 75 moves to the lower portions of the slots 77. The slots 77 are slanted relative to the direction of travel of the pin 75 so that as the slots 77 move relative to the pin 75 during the opening operation the main contact members 71 are cammed a slight distance to the left and during the closing operation the main contact members 71 are cammed a slight distance to the right to thereby provide a wiping action that serves to keep the contacts 95, 15 and 97, 13 clean.

Another embodiment of the invention is illustrated in F IGS. 9-13. The contact structure shown in FIGS. 9l3 can be used in a circuit breaker of the general type disclosed in FIGS. 1 and 3. In this embodiment, a rigid conductor 141 is provided with a cavity 143, and a flat generally straight leaf-spring resilient conductor 145 is supported on the conductor 141 by means of a rivet 147 with the free end of the resilient conductor 145 extending over the cavity 143 toward a fixed contact 149 that is fixedly secured to the conductor 14]. An arcing contact 151 is supported on the free end of the resilient conductor 145. A U-shaped magnetic steel arc-runner 153 is fixed to the resilient conductor 145 by means of a rivet 155 with the free end of the upper leg of the arc-runner I53 extending toward the bight portions of a plurality of stacked generally U- shaped magnetic plates 159. A main contact 160 and an arcing contact 161 are supported on the free end ofa contact arm 163 that is suitably supported for pivotal movement about an axis 165, and that is electrically connected to another rigid conductor (not shown) by means ofa flexible conductor 167.

In the embodiment shown in FIGS. 9-13, only the one movable contact arm 163 is provided to carry the current in the closed position of the contacts. As the contact arm 163 is moved from the closed position seen in FIG. 9 to the open position seen in FIG. 12, the contact 160 first disengages from the fixed stationary contact 149 whereupon the current from the contact arm 163 to the conductor 141 flows through the arcing contact 161, the arcing contact 151 and the flexible resilient conductor to the rigid conductor 141. As the contact 161 separates from the contact 151 (FIG. 11) an are 171 is drawn, which are rides up the arc-horn 169 of the contact arm 163 and which are is carried at the lower end thereof on the magnetic arc-runner 153 into the bight portions of the stacked magnetic plates 159 where the arc is broken up into a plurality of serially related arcs to be extinguished. With this construction, the current through the arc-horn 169, the arc, the arc-runner 153 and resilient conductor 145 forms an inside loop at A" and an inside loop at B, with the arc moving in the direction of the arrow (FIG. 11) toward the bight portions of the arc plates (FIG. 9), so that the loop effect contributes in moving the are into the arc plates.

We claim:

1. A circuit breaker comprising an arc-extinguishing structure, contact means comprising a stationary contact structure supported in proximity to said arc-extinguishing structure, a movable contact structure movable to a closed position in engagement with said stationary contact structure and to an open position disengaged from said stationary contact structure, said stationary contact structure comprising a fixed contact, a resiliently movable conductor, and arcing contact supported on said resiliently movable conductor, said contact means being constructed and arranged such that during closing operations said movable contact structure engages said arcing contact before engagement with said fixed contact to charge said resiliently movable conductor and during opening operations said charged resiliently movable conductor follows said movable contact structure a limited distance such that said movable contact structure disengages from said fixed contact before said movable contact structure disengages from said arcing contact, an arc-runner supported on said resiliently movable conductor to carry arcs away from said arcing contact into said arc-extinguishing structure, a rigid conductor, said fixed contact being supported on said rigid conductor, an elongated resiliently movable leaf-spring conductor fixedly supported at one end thereof on said rigid conductor on a first side of said fixed contact and extending toward said fixed contact with the free end thereof being positioned in proximity to said fixed contact, said arcing contact being supported on the free end of said resiliently movable leaf-spring conductor, said movable contact structure being movably supported on the side of said fixed contact opposite said first side, said arc-runner comprising an elongated member supported at one end thereof on said resiliently movable leaf-spring conductor in proximity to said arcing contact with the main body portion and the other end of said arcrunner being spaced from said resiliently movable leaf-spring conductor.

2. A circuit breaker according to claim 1, said arc-extinguishing structure comprising a plurality of stacked slotted magnetic plates stacked with the slots thereof in alignment, said resiliently movable leaf-spring conductor and said arcing contact being positioned within the aligned slots of said magnetic plates with said free end of said arc-runner extending toward the bight portions of said plates.

3. A circuit breaker comprising an arc-extinguishing structure, contact means comprising a stationary contact structure supported in proximity to said arc-extinguishing structure, a movable contact structure movable to a closed position in engagement with said stationary contact structure and to an open position disengaged from said stationary contact structure, said stationary contact structure comprising a fixed contact, a resiliently movable conductor, an arcing contact supported on said resiliently movable conductor, said contact means being constructed and arranged such that during closing operations said movable contact structure engages said arcing contact before engagement with said fixed contact to charge said resiliently movable conductor and during opening operations said charged resiliently movable conductor follows said movable contact structure a limited distance such that said movable contact structure disengages from said fixed contact before said movable contact structure disengages from said arcing contact, an arc-runner supported on said resiliently movable conductor to carry arcs away from said arcing contact into said arc-extinguishing structure, a rigid conductor, said fixed contact being supported on said rigid conductor, said resiliently movable conductor comprising and elongated resiliently movable conductor fixedly supported at one end thereof on said rigid conductor on a first side of said fixed contact and extending toward said fixed contact with the free end thereof being positioned in proximity to said fixed contact, said arcing contact being supported on the free end of said resiliently movable conductor, said movable contact structure being movably supported on the side of said fixed contact opposite said first side, said arc-runner comprising a generally U-shaped member supported at one leg thereof on said resiliently movable conductor with the outer side of said one leg engaging said resiliently movableconductor and with the other leg thereof being spaced from said resiliently movable conductor, said generally U-shaped member being supported on said resiliently movable conductor with the bight portion thereof being in proximity to said arcing contact and with the legs thereof extending away from said arcing contact in the direction into said arc-extinguishing structure.

4. A circuit breaker according to claim 3, said arc-extinguishing structure comprising a plurality of magnetic slotted plates supported in a stacked relationship with the slots thereof in alignment, said contact arm moving within said aligned slots, and said other leg of said arc-runner extending generally toward the bight portions of said stacked magnetic plates.

5. A circuit breaker comprising an arc-extinguishing structure, contact means comprising a stationary contact structure supported in proximity to said arc-extinguishing structure, a movable contact structure movable to a closed position in engagement with said stationary contact structure and to an open position disengaged from said stationary contact structure, said stationary contact structure comprising a fixed contact, an elongated resiliently movable leaf spring conductor, and arcing contact supported on said leaf-spring conductor, said contact means being constructed and arranged such that during closing operations said movable contact structure engages said arcing contact before engagement with said fixed contact to charge said leaf-spring conductor and during opening operations said charged leaf-spring conductor follows said movable contact structure a limited distance such that said movable contact structure disengages from said fixed contact before said movable contact structure disengages from said arcing contact, an arc-runner supported on said leaf-spring conductor to carry arcs away from said arcing contact into said arc-extinguishing structure, a rigid conductor, said fixed contact being supported on said rigid conductor at the front of said rigid conductor, said leaf-spring conductor being fixedly supported at one end thereof on said rigid conductor at the front of said rigid conductor on a first side of said fixed contact and extending toward said fixed contact with the free end thereof being positioned in proximity to said fixed contact, said arcing contact being supported on said leaf-spring conductor, at the free end of said leaf-spring conductor, said movable contact structure being movably supported on the side of said fixed contact opposite said first side, said arcrunner being supported on said leaf-spring conductor to carry arcs away from said arcing contact into said arc-extinguishing structure, said leaf-spring conductor in extending from the support thereof toward said fixed contact also extending from the support thereof frontward away from the front of said rigid conductor, and said arc-runner being an elongated generally straight arc-runner supported at one end thereof on the front of said leaf-spring conductor in proximity to said arcing contact and extending generally toward the supported end of said leaf-spring conductor with the other end of said arc-runner being spaced from said leaf-spring'conductor.

6. A circuit breaker according to claim 5, said arc-extinguishing structure comprising a plurality of slotted stacked magnetic plates stacked with the slots thereof in alignment, said elongated leaf-spring conductor being positioned with the supported end thereof in the slot-portion of said slotted stacked magnetic plates.

7. A circuit breaker comprising an arc-extinguishing structure, contact means comprising a stationary contact structure supported in proximity to said arc-extinguishing structure, a movable contact structure movable to a closed position in engagement with said stationary contact structure and to an open position disengaged from said stationary contact structure, said stationary contact structure comprising a fixed contact, an elongated resiliently movable leaf-spring conductor, an arcing contact supported on said leaf-spring conductor, said contact means being constructed and arranged such that during closing operations said movable contact structure engages said arcing contact before engagement with said fixed contact to charge said leaf-spring conductor and during opening operations said charged leaf-spring conductor follows said movable contact structure a limited distance such that said movable contact structure disengages from said fixed contact before said movable contact structure disengages from said arcing contact, an arc-runner supported on said leaf-spring conductor to carry arcs away from said arcing contact into said arc-extinguishing structure, a rigid conductor, said fixed contact being supported on said rigid conductor at the front of said rigid conductor, said leaf-spring conductor being fixedly supported at one end thereof on said rigid conductor at the front of said rigid conductor on a first side of said fixed contact and extending toward said fixed contact with the free end thereof being" positioned in proximity to said fixed contact, said arcing contact being supported on said leaf-spring conductor at the free end of said leaf-spring conductor, said movable contact structure being movably supported on the side of said fixed contact opposite said first side, said arcrunner being supported on said leaf-spring conductor to carry arcs away from said arcing contact into said arc-extinguishing structure, said arc-runner being a generally U-shaped member supported at one leg thereof on said leaf-spring conductor with the outer side of said one leg engaging said leaf-spring conductor and with the other leg thereof being spaced from said leaf-spring conductor, said arc-runner being supported on said leaf-spring conductor with the bight portion thereof being in proximity to said arcing contact and with the legs thereof extending away from said arcing contact in the direction into said arc-extinguishing structure.

8. A circuit breaker comprising an arc-extinguishing structure, contact means comprising a stationary contact structure supported in proximity to said arc-extinguishing structure, a movable contact structure movable to a closed position in engagement with said stationary contact structure and to an open position disengaged from said stationary contact structure, said stationary contact structure comprising a fixed contact, a resiliently movable conductor, an arcing contact supported on said resiliently movable conductor, said contact means being constructed and arranged such that during closing operations said movable contact structure engages said arcing contact before engagement with said fixed contact to charge said resiliently movable conductor and during opening operations said charged resiliently movable conductor follows said movable contact structure a limited distance such that said movable contact structure disengages from said fixed contact before said movable contact structure disengages from said arcing contact, an arc-runner supported on said resiliently movable conductor to carry arcs away from said arcing contact into said arc-extinguishing structure, said movable contact structure comprising a movable contact support member movable to said closed and open positions, said movable contact structure comprising a movable contact arm and contact means on said movable contact arm, said movable contact arm being supported on said movable contact support member for movement with said movable contact support member between open and closed positions and for limited movement relative to said movable contact support member, said movable contact structure comprising Spring means biasing said movable contact arm relative to said movable contact support member to provide contact pressure between said contact means and said fixed contact in the closed position of said contact structures, during closing operations as said movable contact support member moves to the closed position said contact means engages said arcing contact and charges said resiliently movable conductor and thereafter said contact means engages said fixed contact and thereafter said spring means is charged as said movable contact support member moves to the fully closed position relative to said movable contact arm while said contact means engages said fixed contact, during opening operations said movable contact support member moves away from said stationary contact structure while said contact means remains in engagement with said fixed contact and arcing contact under the bias of said spring means until said limited movement of said movable contact arm relative to said movable contact support member is taken up and thereafter said movable contact arm moves with said movable contact support member to the open position during which movement said contact means disengages from said fixed contact as said resiliently movable conductor follows said movable contact structure a limited distance and thereafter said contact means disengages from said arcing contact drawing an are that moves on said arc-runner into said arc-extinguishing structure.

9. A circuit breaker according to claim 8, a rigid conductor, said fixed contact being supported on said rigid conductor, said resiliently movable conductor comprising an elongated conductor fixedly supported at one end thereof on said rigid conductor on a first side of said fixed contact and extending toward said fixed contact with the free end thereof being positioned in proximity to said fixed contact, said arcing contact being supported on the free end of said resiliently movable conductor, and said movable contact structure being movably supported on the side of said fixed contact opposite said first side.

10. A circuit breaker according to claim 9, said resiliently movable conductor comprising an elongated leaf-spring conductor, said arc-runner comprising an elongated member supported at one endthereof on said leaf-spring conductor in proximity to said arcing contact with'the main body portion and the other end of said arc-runner being spaced from said leaf-spring conductor.

11. A circuit breaker according to claim 9, said fixed contact being supported on the front of said rigid conductor, said resiliently movable conductor comprising an elongated leafspring conductor fixedly supported at one end thereof on the front of said rigid conductor on said first side of said fixed contact and extending toward said fixed contact with the free end thereof being spaced from said rigid conductor, said arcing contact being supported on said leaf-spring conductor at the free end of said leaf-spring conductor, and said arc-runner being supported on said leaf-spring conductor to carry arcs away from said arcing contact into said arc-extinguishing structure.

12. A circuit breaker according to claim 11, said elongated leaf-spring conductor in extending from the support thereof toward said fixed contact also extending from the support thereof frontward away from the front of said rigid conductor, and said arc-runner being an elongated generally straight arcrunner supported at one end thereof on the front of said leafspring conductor in proximity to said arcing contact and extending generally toward the supported end of said leaf-spring conductor with the other end of said elongated generally straight arc-runner being spaced from said leaf-spring conductor.

13. A circuit breaker according to claim 12, said arc-extinguishing structure comprising a plurality of slotted stacked magnetic plates stacked with the slots thereof in alignment, said elongated leaf-spring conductor being positioned with the supported end thereof in the slot-portion of said slotted stacked magnetic plates.

14. A circuit breaker comprising a circuit-breaker structure, said circuit-breaker structure comprising a first stationary conductor, a second stationary conductor spaced from said first stationary. conductor, an arc-extinguishing structure, a first and arcing stationary contact means on said first stationary conductor in proximity to said arc-extinguishing structure, a second stationary contact means on said first stationary conductor, a third stationary contact means on said second stationary conductor,

a movable contact device, said movable contact device comprising a movable support member, an arcing-contact support arm connected to said support member for movement with said support member between open and closed positions and for limited movement relative to said support member, a first and arcing movable contact on said arcing-contact support arm, contact-pressure spring means biasing said arcing-contact support arm relative to said support member toward said first and arcing stationary contact means, a pair of bridging contact support arms supported on said support member on opposite sides of said arcing-contact support arm for movement with said support member between open and closed positions and for limited movement relative to said support member, a separate second movable contact and a separate third movable contact supported on each of said bridging contact support arms, said contact-pressure spring means biasing said bridging contact support arms relative to said support member toward said second and third stationary contact means,

said movable contact device being movable between closed and open positions to close and open an electric circuit, in the closed position of said contacts said first and arcing movable contact engaging said first and arcing stationary contact means, said second movable contacts engaging said second stationary contact means and said third movable contacts engaging said third stationary contact means,

during each opening operation of said movable contact device said second movable contacts disengaging from said second stationary contact means to transfer current to said arcing-contact support arm and thereafter said arcing movable contact moving away from said first and arcing stationary contact means,

said first and arcing stationary contact means comprising a fixed contact on said first stationary conductor and a resiliently movable conductor on said first stationary conductor and a stationary arcing contact on said resiliently movable conductor and an arc-runner on said resiliently movable conductor,

and during opening operations said second movable contacts disengaging from said second stationary contact means to transfer current to said arcing-contact support arm and thereafter said first and arcing contact moving away from said fixed contact as said stationary contact on said resiliently movable conductor follows said first and arcing contact a limited distance and thereafter said first and arcing contact disengaging from said stationary arcing contact drawing an are that moves on said arc-runner into said arc-extinguishing structure.

15. A circuit breaker according to claim 14, said resiliently movable conductor comprising an elongated conductor fixedly supported at one end thereof on said fist stationary conductor on a first side of said fixed contact and extending toward said fixed contact with the free end thereof being positioned in proximity to said fixed contact, said stationary contact being carried on the free end of said resiliently movable conductor, and said movable contact structure being movably supported on the side of said fixed contact opposite said first side.

16. A circuit breaker according to claim 15, said fixed contact being supported on the front of said first stationary conductor, said resiliently movable conductor comprising an elongated leaf-spring conductor fixedly supported at one end thereof on the front of said first stationary conductor on said first side of said fixed contact and extending toward said fixed contact with the free end thereof being spaced from said first stationary conductor, said stationary arcing contact being supported on said leaf-spring conductor at the free end of said leaf-spring conductor, and said arc-runner being supported on said leaf-spring conductor to carry arcs away from said stationary arcing contact into said arc-extinguishing structure. 

1. A circuit breaker comprising an arc-extinguishing structure, contact means comprising a stationary contact structure supported in proximity to said arc-extinguishing structure, a movable contact structure movable to a closed position in engagement with said stationary contact structure and to an open position disengaged from said stationary contact structure, said stationary contact structure comprising a fixed contact, a resiliently movable conductor, and arcing contact supported on said resiliently movable conductor, said contact means being constructed and arranged such that during closing operations said movable contact structure engages said arcing contact before engagement with said fixed contact to charge said resiliently movable condUctor and during opening operations said charged resiliently movable conductor follows said movable contact structure a limited distance such that said movable contact structure disengages from said fixed contact before said movable contact structure disengages from said arcing contact, an arcrunner supported on said resiliently movable conductor to carry arcs away from said arcing contact into said arc-extinguishing structure, a rigid conductor, said fixed contact being supported on said rigid conductor, an elongated resiliently movable leafspring conductor fixedly supported at one end thereof on said rigid conductor on a first side of said fixed contact and extending toward said fixed contact with the free end thereof being positioned in proximity to said fixed contact, said arcing contact being supported on the free end of said resiliently movable leaf-spring conductor, said movable contact structure being movably supported on the side of said fixed contact opposite said first side, said arc-runner comprising an elongated member supported at one end thereof on said resiliently movable leaf-spring conductor in proximity to said arcing contact with the main body portion and the other end of said arc-runner being spaced from said resiliently movable leaf-spring conductor.
 2. A circuit breaker according to claim 1, said arc-extinguishing structure comprising a plurality of stacked slotted magnetic plates stacked with the slots thereof in alignment, said resiliently movable leaf-spring conductor and said arcing contact being positioned within the aligned slots of said magnetic plates with said free end of said arc-runner extending toward the bight portions of said plates.
 3. A circuit breaker comprising an arc-extinguishing structure, contact means comprising a stationary contact structure supported in proximity to said arc-extinguishing structure, a movable contact structure movable to a closed position in engagement with said stationary contact structure and to an open position disengaged from said stationary contact structure, said stationary contact structure comprising a fixed contact, a resiliently movable conductor, an arcing contact supported on said resiliently movable conductor, said contact means being constructed and arranged such that during closing operations said movable contact structure engages said arcing contact before engagement with said fixed contact to charge said resiliently movable conductor and during opening operations said charged resiliently movable conductor follows said movable contact structure a limited distance such that said movable contact structure disengages from said fixed contact before said movable contact structure disengages from said arcing contact, an arc-runner supported on said resiliently movable conductor to carry arcs away from said arcing contact into said arc-extinguishing structure, a rigid conductor, said fixed contact being supported on said rigid conductor, said resiliently movable conductor comprising and elongated resiliently movable conductor fixedly supported at one end thereof on said rigid conductor on a first side of said fixed contact and extending toward said fixed contact with the free end thereof being positioned in proximity to said fixed contact, said arcing contact being supported on the free end of said resiliently movable conductor, said movable contact structure being movably supported on the side of said fixed contact opposite said first side, said arc-runner comprising a generally U-shaped member supported at one leg thereof on said resiliently movable conductor with the outer side of said one leg engaging said resiliently movable conductor and with the other leg thereof being spaced from said resiliently movable conductor, said generally U-shaped member being supported on said resiliently movable conductor with the bight portion thereof being in proximity to said arcing contact and with the legs thereof extending away from said arcing contact in the direction into said arc-extinguishing strUcture.
 4. A circuit breaker according to claim 3, said arc-extinguishing structure comprising a plurality of magnetic slotted plates supported in a stacked relationship with the slots thereof in alignment, said contact arm moving within said aligned slots, and said other leg of said arc-runner extending generally toward the bight portions of said stacked magnetic plates.
 5. A circuit breaker comprising an arc-extinguishing structure, contact means comprising a stationary contact structure supported in proximity to said arc-extinguishing structure, a movable contact structure movable to a closed position in engagement with said stationary contact structure and to an open position disengaged from said stationary contact structure, said stationary contact structure comprising a fixed contact, an elongated resiliently movable leaf spring conductor, and arcing contact supported on said leaf-spring conductor, said contact means being constructed and arranged such that during closing operations said movable contact structure engages said arcing contact before engagement with said fixed contact to charge said leaf-spring conductor and during opening operations said charged leaf-spring conductor follows said movable contact structure a limited distance such that said movable contact structure disengages from said fixed contact before said movable contact structure disengages from said arcing contact, an arc-runner supported on said leaf-spring conductor to carry arcs away from said arcing contact into said arc-extinguishing structure, a rigid conductor, said fixed contact being supported on said rigid conductor at the front of said rigid conductor, said leaf-spring conductor being fixedly supported at one end thereof on said rigid conductor at the front of said rigid conductor on a first side of said fixed contact and extending toward said fixed contact with the free end thereof being positioned in proximity to said fixed contact, said arcing contact being supported on said leaf-spring conductor, at the free end of said leaf-spring conductor, said movable contact structure being movably supported on the side of said fixed contact opposite said first side, said arc-runner being supported on said leaf-spring conductor to carry arcs away from said arcing contact into said arc-extinguishing structure, said leaf-spring conductor in extending from the support thereof toward said fixed contact also extending from the support thereof frontward away from the front of said rigid conductor, and said arc-runner being an elongated generally straight arc-runner supported at one end thereof on the front of said leaf-spring conductor in proximity to said arcing contact and extending generally toward the supported end of said leaf-spring conductor with the other end of said arc-runner being spaced from said leaf-spring conductor.
 6. A circuit breaker according to claim 5, said arc-extinguishing structure comprising a plurality of slotted stacked magnetic plates stacked with the slots thereof in alignment, said elongated leaf-spring conductor being positioned with the supported end thereof in the slot-portion of said slotted stacked magnetic plates.
 7. A circuit breaker comprising an arc-extinguishing structure, contact means comprising a stationary contact structure supported in proximity to said arc-extinguishing structure, a movable contact structure movable to a closed position in engagement with said stationary contact structure and to an open position disengaged from said stationary contact structure, said stationary contact structure comprising a fixed contact, an elongated resiliently movable leaf-spring conductor, an arcing contact supported on said leaf-spring conductor, said contact means being constructed and arranged such that during closing operations said movable contact structure engages said arcing contact before engagement with said fixed contact to charge said leaf-spring conductor and during opening operations said charged leaf-spring conductor follows said movaBle contact structure a limited distance such that said movable contact structure disengages from said fixed contact before said movable contact structure disengages from said arcing contact, an arc-runner supported on said leaf-spring conductor to carry arcs away from said arcing contact into said arc-extinguishing structure, a rigid conductor, said fixed contact being supported on said rigid conductor at the front of said rigid conductor, said leaf-spring conductor being fixedly supported at one end thereof on said rigid conductor at the front of said rigid conductor on a first side of said fixed contact and extending toward said fixed contact with the free end thereof being positioned in proximity to said fixed contact, said arcing contact being supported on said leaf-spring conductor at the free end of said leaf-spring conductor, said movable contact structure being movably supported on the side of said fixed contact opposite said first side, said arc-runner being supported on said leaf-spring conductor to carry arcs away from said arcing contact into said arc-extinguishing structure, said arc-runner being a generally U-shaped member supported at one leg thereof on said leaf-spring conductor with the outer side of said one leg engaging said leaf-spring conductor and with the other leg thereof being spaced from said leaf-spring conductor, said arc-runner being supported on said leaf-spring conductor with the bight portion thereof being in proximity to said arcing contact and with the legs thereof extending away from said arcing contact in the direction into said arc-extinguishing structure.
 8. A circuit breaker comprising an arc-extinguishing structure, contact means comprising a stationary contact structure supported in proximity to said arc-extinguishing structure, a movable contact structure movable to a closed position in engagement with said stationary contact structure and to an open position disengaged from said stationary contact structure, said stationary contact structure comprising a fixed contact, a resiliently movable conductor, an arcing contact supported on said resiliently movable conductor, said contact means being constructed and arranged such that during closing operations said movable contact structure engages said arcing contact before engagement with said fixed contact to charge said resiliently movable conductor and during opening operations said charged resiliently movable conductor follows said movable contact structure a limited distance such that said movable contact structure disengages from said fixed contact before said movable contact structure disengages from said arcing contact, an arc-runner supported on said resiliently movable conductor to carry arcs away from said arcing contact into said arc-extinguishing structure, said movable contact structure comprising a movable contact support member movable to said closed and open positions, said movable contact structure comprising a movable contact arm and contact means on said movable contact arm, said movable contact arm being supported on said movable contact support member for movement with said movable contact support member between open and closed positions and for limited movement relative to said movable contact support member, said movable contact structure comprising spring means biasing said movable contact arm relative to said movable contact support member to provide contact pressure between said contact means and said fixed contact in the closed position of said contact structures, during closing operations as said movable contact support member moves to the closed position said contact means engages said arcing contact and charges said resiliently movable conductor and thereafter said contact means engages said fixed contact and thereafter said spring means is charged as said movable contact support member moves to the fully closed position relative to said movable contact arm while said contact means engages said fixed contact, during opening operations said movable contact suppOrt member moves away from said stationary contact structure while said contact means remains in engagement with said fixed contact and arcing contact under the bias of said spring means until said limited movement of said movable contact arm relative to said movable contact support member is taken up and thereafter said movable contact arm moves with said movable contact support member to the open position during which movement said contact means disengages from said fixed contact as said resiliently movable conductor follows said movable contact structure a limited distance and thereafter said contact means disengages from said arcing contact drawing an arc that moves on said arc-runner into said arc-extinguishing structure.
 9. A circuit breaker according to claim 8, a rigid conductor, said fixed contact being supported on said rigid conductor, said resiliently movable conductor comprising an elongated conductor fixedly supported at one end thereof on said rigid conductor on a first side of said fixed contact and extending toward said fixed contact with the free end thereof being positioned in proximity to said fixed contact, said arcing contact being supported on the free end of said resiliently movable conductor, and said movable contact structure being movably supported on the side of said fixed contact opposite said first side.
 10. A circuit breaker according to claim 9, said resiliently movable conductor comprising an elongated leaf-spring conductor, said arc-runner comprising an elongated member supported at one end thereof on said leaf-spring conductor in proximity to said arcing contact with the main body portion and the other end of said arc-runner being spaced from said leaf-spring conductor.
 11. A circuit breaker according to claim 9, said fixed contact being supported on the front of said rigid conductor, said resiliently movable conductor comprising an elongated leaf-spring conductor fixedly supported at one end thereof on the front of said rigid conductor on said first side of said fixed contact and extending toward said fixed contact with the free end thereof being spaced from said rigid conductor, said arcing contact being supported on said leaf-spring conductor at the free end of said leaf-spring conductor, and said arc-runner being supported on said leaf-spring conductor to carry arcs away from said arcing contact into said arc-extinguishing structure.
 12. A circuit breaker according to claim 11, said elongated leaf-spring conductor in extending from the support thereof toward said fixed contact also extending from the support thereof frontward away from the front of said rigid conductor, and said arc-runner being an elongated generally straight arc-runner supported at one end thereof on the front of said leaf-spring conductor in proximity to said arcing contact and extending generally toward the supported end of said leaf-spring conductor with the other end of said elongated generally straight arc-runner being spaced from said leaf-spring conductor.
 13. A circuit breaker according to claim 12, said arc-extinguishing structure comprising a plurality of slotted stacked magnetic plates stacked with the slots thereof in alignment, said elongated leaf-spring conductor being positioned with the supported end thereof in the slot-portion of said slotted stacked magnetic plates.
 14. A circuit breaker comprising a circuit-breaker structure, said circuit-breaker structure comprising a first stationary conductor, a second stationary conductor spaced from said first stationary conductor, an arc-extinguishing structure, a first and arcing stationary contact means on said first stationary conductor in proximity to said arc-extinguishing structure, a second stationary contact means on said first stationary conductor, a third stationary contact means on said second stationary conductor, a movable contact device, said movable contact device comprising a movable support member, an arcing-contact support arm connected to said support member for movemEnt with said support member between open and closed positions and for limited movement relative to said support member, a first and arcing movable contact on said arcing-contact support arm, contact-pressure spring means biasing said arcing-contact support arm relative to said support member toward said first and arcing stationary contact means, a pair of bridging contact support arms supported on said support member on opposite sides of said arcing-contact support arm for movement with said support member between open and closed positions and for limited movement relative to said support member, a separate second movable contact and a separate third movable contact supported on each of said bridging contact support arms, said contact-pressure spring means biasing said bridging contact support arms relative to said support member toward said second and third stationary contact means, said movable contact device being movable between closed and open positions to close and open an electric circuit, in the closed position of said contacts said first and arcing movable contact engaging said first and arcing stationary contact means, said second movable contacts engaging said second stationary contact means and said third movable contacts engaging said third stationary contact means, during each opening operation of said movable contact device said second movable contacts disengaging from said second stationary contact means to transfer current to said arcing-contact support arm and thereafter said arcing movable contact moving away from said first and arcing stationary contact means, said first and arcing stationary contact means comprising a fixed contact on said first stationary conductor and a resiliently movable conductor on said first stationary conductor and a stationary arcing contact on said resiliently movable conductor and an arc-runner on said resiliently movable conductor, and during opening operations said second movable contacts disengaging from said second stationary contact means to transfer current to said arcing-contact support arm and thereafter said first and arcing contact moving away from said fixed contact as said stationary contact on said resiliently movable conductor follows said first and arcing contact a limited distance and thereafter said first and arcing contact disengaging from said stationary arcing contact drawing an arc that moves on said arc-runner into said arc-extinguishing structure.
 15. A circuit breaker according to claim 14, said resiliently movable conductor comprising an elongated conductor fixedly supported at one end thereof on said fist stationary conductor on a first side of said fixed contact and extending toward said fixed contact with the free end thereof being positioned in proximity to said fixed contact, said stationary contact being carried on the free end of said resiliently movable conductor, and said movable contact structure being movably supported on the side of said fixed contact opposite said first side.
 16. A circuit breaker according to claim 15, said fixed contact being supported on the front of said first stationary conductor, said resiliently movable conductor comprising an elongated leaf-spring conductor fixedly supported at one end thereof on the front of said first stationary conductor on said first side of said fixed contact and extending toward said fixed contact with the free end thereof being spaced from said first stationary conductor, said stationary arcing contact being supported on said leaf-spring conductor at the free end of said leaf-spring conductor, and said arc-runner being supported on said leaf-spring conductor to carry arcs away from said stationary arcing contact into said arc-extinguishing structure.
 17. A circuit breaker according to claim 16, said elongated leaf-spring conductor in extending from the support thereof toward said fixed contact also extending from the support thereof frontward away from the front of said first stationary conductor, and said arc-runner bEing an elongated generally straight arc-runner supported at one end thereof on the front of said leaf-spring conductor in proximity to said stationary arcing contact and extending generally toward the supported end of said leaf-spring conductor with the other end of said elongated generally straight arc-runner being spaced from said leaf-spring conductor. 